It is known to partition wireless communication networks into cells so that different base stations can provide service to different cells each of which covers a different geographic area. To reduce interference between base stations that serve adjacent geographic areas, base stations can be assigned broadcast control channel frequencies according to a re-use pattern so as to minimize the likelihood that two base stations covering adjacent geographic areas use the same control channel frequency to service mobile stations.
For example, it is known to provide a group of twelve base station transceivers covering a contiguous geographic area with twelve different control channel frequencies. This pattern of control channel frequencies can be repeated for a second group of base stations even though the second group of base stations is located adjacent to the first group. This type of frequency re-use patterning can reduce the likelihood of interference between base stations that use the same control channel frequencies.
One of the activities that commonly arises in a wireless communications system such as the ones described above, is that of handover. In particular, when a mobile station is located within a geographic area serviced by a base station, that base station may currently provide service to the mobile station. As the mobile station moves within the area covered by the network, another base station may provide better service to the mobile station due to the new location of the mobile station. Accordingly, it is known to handover service of the mobile station from a currently serving base station to a neighboring base station, which may provide better service.
One of the ways in which mobile stations assist in the evaluation for a handover is to periodically send measurement reports of nearby base stations to the network. In the process of doing these measurements, the mobile station maintains what is commonly referred to as a toplist. The toplist maintained by the mobile station records a number of neighboring base stations, which may be likely candidates for handover given a mobile station's current location. The measurements reported to the network contain the basestation identity code (BSIC) for each basestation in the toplist. Also, the base station identity code is verified periodically by the mobile station for the reported base stations in the toplist.
It is an issue in many dense network environments, that these measurement reports, which must include the BSIC for each measurement in some networks, be made rapidly enough so that a handover may be completed before the mobile moves out of range of the serving base station. It is a further issue that the BSIC can be determined by demodulating/decoding the received signal only at certain times.